anaphylaxis

American  

[an-uh-fuh-lak-sis] / ˌæn ə fəˈlæk sɪs /

noun

Pathology.

1. exaggerated allergic reaction to a foreign protein resulting from previous exposure to it.

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anaphylaxis British  

/ ˌænəfɪˈlæksɪs /

noun

1. extreme sensitivity to an injected antigen, esp a protein, following a previous injection

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anaphylaxis Scientific  

/ ăn′ə-fə-lăk′sĭs /

1. See anaphylactic shock

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Other Word Forms

• anaphylactic adjective
• anaphylactically adverb
• antianaphylactic adjective
• pseudoanaphylactic adjective

Etymology

Origin of anaphylaxis

First recorded in 1905–10; ana- + (pro)phylaxis

Compare meaning

How does anaphylaxis compare to similar and commonly confused words? Explore the most common comparisons:

• anaphylaxis vs. anaphylactic shock

Example Sentences

The results also pointed to an extreme immune response consistent with fatal anaphylaxis.

From Science Daily • Dec. 17, 2025

The immune system tries to fight them off, triggering symptoms ranging from hives and diarrhea to anaphylaxis, a life-threatening condition.

From Los Angeles Times • Oct. 20, 2025

Among the most common co-occurring illnesses were chronic fatigue syndrome and mast cell activation syndrome, or MCAS, a condition where patients experience intense episodes of diarrhea, hives, vomiting, and, in many cases, life-threatening anaphylaxis attacks.

From Slate • Sep. 15, 2025

An inquest at Milton Keynes Coroner's Court this week confirmed Lily died on 23 June 2024 from a cardio-respiratory arrest caused by anaphylaxis and triggered by food.

From BBC • Jun. 21, 2025

The conditions which render a person liable to develop anaphylaxis and the mechanism by which it is established are as yet imperfectly understood.

From Manual of Surgery Volume First: General Surgery. Sixth Edition. by Thomson, Alexis